Feedback from the First Stars: Chemical Abundances in the First Billion Years after the Big Bang

点击翻译按钮获取中文摘要

A great deal of work remains to understand how the first stars in the Universe formed and how their formation and life cycles affected the formation of the first galaxies in the Universe. Understanding these essential details will provide important clues to understanding the formation and life history of our own Galaxy and many others. This project aims to track the time history of heavy chemical elements in the intergalactic medium (IGM) at very high redshift. Because most researchers believe that heating from supernovae and/or active galactic nuclei (AGN) played a vital role in galaxy assembly, the principal investigator (PI) has chosen to study the heavy elements, which are a byproduct of this heating "feedback." The PI will address the following specific scientific questions: (1) Is there a decline in the C IV abundance as the epoch of reionization is approached? (2) Is there a change in the ionization structure of heavy element systems at redshift around 6? (3) Do the large differences in absorption properties between QSO sightlines at redshift 6 reflect cosmic variance or a signature of stochastic early star formation? (4) What mechanism populates galaxy haloes with cold baryons (seen in Mg II) at early times?The broader impacts of this project include important educational components. A graduate student will be supported for the three years of this grant, and the PI works closely with his institution to mentor undergraduates in research and astronomical observing activities. The PI also has an excellent track record in working with students from groups underrepresented in the physical sciences.